HPOP Drag
Set options for modeling drag for the HPOP propagator.
Syntax
HPOP <ObjectPath> Drag {DragState} <Coeff> <AreaMassRatio> {"AtmDensModel"} [{LowAltAtmDensityMdl} <DensityBlendingAltRange>]
Related Commands
Description
The HPOP Drag command allows you to set drag model options for propagating a satellite's or missile's orbit using the high-precision orbit propagator (HPOP) module.
This command is valid for Satellites and Missiles.
{DragState} can be On or Off.
If {DragState} is On enter <Coeff>, <AreaMassRatio> and {"AtmDensModel"}.
<Coeff> is a real number between -100.0 and 100.0.
<AreaMassRatio> is a real number between 0.0 and 9999.0, and is entered in m^2/kg.
Valid values for {"AtmDensModel"} and their associated <Parameters> are outlined in the Table below. The table also lists the object(s) for which each model is valid. Only atmosphere models that are valid to the ground can be used for missiles.
Enter {LowAltAtmDensityMdl} and <DensityBlendingAltRange> to specify values for low altitude atmospheric density model. If included, both values must be entered.
{LowAltAtmDensityMdl} is the lower altitude atmospheric density model. Valid values are "MSISE 1990" and "NRLMSISE 2000".
<DensityBlendingAltRange> is the range of overlap for which the density models will be blended. This is a real number between 0.0 and 1000.0km. Enter the value in Connect distance units.
If {DragState} is Off, no other values should be entered.
| {"AtmDensModel"} | <Parameters> | Valid for: |
|---|---|---|
| "Harris-Priester" | Additional values can be set manually or via a flux/geomag file:
| Satellite, Missile |
| "1976 Standard" | N/A | Satellite, Missile |
| "Jacchia 1960" | N/A | Satellite, Missile |
| "Jacchia 1971" | Additional values can be set manually or via a flux/geomag file:
| Satellite |
| "Jacchia 1970" | Satellite | |
| "Jacchia-Roberts" | Satellite | |
| "CIRA 1972" | Satellite | |
| "NRLMSISE 2000" | Satellite, Missile | |
| "MSISE 1990" | Satellite, Missile | |
| "MSIS 1986" | Satellite | |
| "<UserModelName>" | "<FilePath>" | Satellite |
<DailyF10.7> and <AverageF10.7> are real numbers between 40 and 10000.
<GeoMagIndex> is a real number between 0.0 and 10.0.
Currently, the only valid "<UserModelName>" is "SampleDensFunc"
For this command to be valid, the satellite or missile must already be defined as using the HPOP propagator.
To set additional drag model options, see the HPOP Options command.
Example
To turn On the Harris-Priester drag model for the ERS1 satellite with a coefficient of 1.04 and an area/mass ratio of 0.22:
HPOP */Satellite/ERS1 Drag On 1.04 0.22 "Harris-Priester" Manual 123
To turn On the MSISE 1990 drag model with a coefficient of 2.08 and an area/mass ratio of 0.175:
HPOP */Satellite/Satellite1 Drag On 2.08 0.175 "MSISE 1990" Manual 120 105 3.5
To turn On the Jacchia 1971 drag model specifying a flux file:
HPOP */Satellite/Satellite1 Drag On 2.08 0.175 "Jacchia 1971" File "C:\STKInstall\DynamicEarthData\stkFluxGeoMag.fxm"
To use a user defined atmosphere drag model, specifying a flux file:
HPOP */Satellite/Satellite1 Drag On 2.08 0.175 "SampleDensFunc" "C:\STKInstall\DynamicEarthData\stkFluxGeoMag.fxm"
To set a low altitude atmosphere model with a blending range of 90000.0 m:
HPOP */Satellite/Satellite1 Drag On 1.04 0.22 "CIRA 1972" Manual 123 124 2.5 "MSISE 1990" 90000.0
ReturnMessage
If activated, Connect returns an acknowledgement message.Group Membership
This command belongs to the following group(s):
Version
11.2.1
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